The current iteration, IP version 4, has its roots in 1980, around the time when people like Ken Olsen, founder of Digital Equipment Corp, still said stupid stuff like: “There is no reason for any individual to have a computer in his home.”

Today is IPv6 Day, a geeky holiday that celebrates the web’s transition to Internet Protocol version 6. There’s been a great deal of lead up to today, and much of it has been preceded by a crisis: The Internet is running out of addresses.

The people who run the internet are expected to announce (update: they announced it) that they’ve allocated the last set of internet addresses today. In a matter of months, the old addresses based on the Internet Protocol version 4, or IPv4, are going to run out.